Iowa Almanac for Sunday, May 17, 2026
"Stop The Construction"
City leaders on both sides of the Mississippi River were excited about the prospects. The existing bridges connecting Iowa to Illinois and Wisconsin were carrying more cars each day than they were designed to, so the idea in 1978 of a new $35 million, four-lane bridge was quite welcome.
But the Higgins' Eye Clam almost put a halt to the project.
Clam hunting was once a profitable business on the Mississippi River, reaching its highest profitability in the late 1800s when several varieties were used in the button industry.
The Higgins' Eye Clam was named for the man who discovered the species in Muscatine in 1857. But by the 1970s, over-harvesting and changing climate led to the clam becoming endangered, with only four known clam beds remaining...including one off City Island at Dubuque, near the bridge construction site.
On May 17, 1978, the Iowa Department of Transportation awarded an $8,000 grant to Loras biology professor Edward Cawley. He and his team set out to determine if the Higgins' Eye Clam would be adversely affected by the bridge project. Construction stopped immediately, and for the next two months, researchers brought a thousand clams to the surface. Only one Higgins' Eye Clam was found, and it died within 24 hours of being transferred to an aquarium.
That led to careful construction of the bridge, so as not to disturb the habitat where the clam was found, just less than 1,000 feet from the bridge itself.
That wasn't the only snag in construction, though. Two years later, construction was halted when a Native American burial site was found on the bluff where the bridge was to connect with Wisconsin. Archaeologists had read a map incorrectly and missed the site originally.
But not long after the Tennessee Valley Authority was stopped from building a project thanks to the snail darter fish, construction of a bridge over the Mississippi River was temporarily stopped in order to protect the Higgins' Eye Clam, on this date in 1978.
And that's Iowa Almanac for May 17th...Listen to the extended audio version of today's story by clicking on the audio player above.
"Stop The Construction"
City leaders on both sides of the Mississippi River were excited about the prospects. The existing bridges connecting Iowa to Illinois and Wisconsin were carrying more cars each day than they were designed to, so the idea in 1978 of a new $35 million, four-lane bridge was quite welcome.
But the Higgins' Eye Clam almost put a halt to the project.
Clam hunting was once a profitable business on the Mississippi River, reaching its highest profitability in the late 1800s when several varieties were used in the button industry.
The Higgins' Eye Clam was named for the man who discovered the species in Muscatine in 1857. But by the 1970s, over-harvesting and changing climate led to the clam becoming endangered, with only four known clam beds remaining...including one off City Island at Dubuque, near the bridge construction site.
On May 17, 1978, the Iowa Department of Transportation awarded an $8,000 grant to Loras biology professor Edward Cawley. He and his team set out to determine if the Higgins' Eye Clam would be adversely affected by the bridge project. Construction stopped immediately, and for the next two months, researchers brought a thousand clams to the surface. Only one Higgins' Eye Clam was found, and it died within 24 hours of being transferred to an aquarium.
That led to careful construction of the bridge, so as not to disturb the habitat where the clam was found, just less than 1,000 feet from the bridge itself.
That wasn't the only snag in construction, though. Two years later, construction was halted when a Native American burial site was found on the bluff where the bridge was to connect with Wisconsin. Archaeologists had read a map incorrectly and missed the site originally.
But not long after the Tennessee Valley Authority was stopped from building a project thanks to the snail darter fish, construction of a bridge over the Mississippi River was temporarily stopped in order to protect the Higgins' Eye Clam, on this date in 1978.
And that's Iowa Almanac for May 17th...Listen to the extended audio version of today's story by clicking on the audio player above.
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Copyright 2026 by Stein Enterprises, L.L.C.
All Rights Reserved.
No use of the material is allowed without prior written permission of the copyright holder.
Copyright 2026 by Stein Enterprises, L.L.C.
